Production of artificial materials



Patented June 22, 1937 PRODUCTION or ARTIFHCIAL MATERIALS Henry Dreyfus, London, England No Drawing. Application April 15, 1930, Serial N43. 444,622. In Great Britain May 17, 1929 3 Claims.

This invention relates to the production of artificial filaments, threads, yarns, ribbons, films or other materials and is more particularly concerned with the production of filaments, threads 5 or other materials having a reduced, subdued or otherwise modified lustre.

With this object in view the invention is especially concerned with the incorporation in the products of insoluble substances and particularly inorganic substances such as insoluble metallic salts or compounds.

According to the present invention insoluble substances and especially metallic compounds or other'inorganic substances are incorporated in artificial threads, yarns, ribbons, films and other materials by adding to the spinning solution or to the base thereof, for example cellulose acetate, the insoluble substance or substances in finely divided form.

I prefer to bring the insoluble substances into i the requisite state of division before addition to the spinning solution or to a constituent thereof, but, as hereinafter described, the invention does not exclude the formation of the insoluble substance in a finely divided state in the solvent used for making up the spinning solution.

, White metallic or other compounds are preferably employed for the purpose of the present invention, and for obvious reasons they should not be extractable by baths or reagents, particularly aqueous baths, with which the goods will be subsequently treated. Thus it .is preferable that the substances should be Water insoluble or substantially so. Substances which I have found particularly valuable are barium sulphate, barium phosphate, lead sulphate, zinc oxide, zinc carbonate, calcium and magnesium carbonates, calcium sulphate and alumina.

It might have been thought that spinning so- 40 lutions containing these substances could not be spun under modern conditions of spinning in which very fine jet orifices are employed owing to choking of the filters and/o'r'of the spinning dies. I have found, however, that this is not the case and that it is possible to reduce the inorganic substances to such a state of subdivision that they will readily pass the filters and the spinning dies. Thus it is found that if the insoluble substance is reduced to aparticle size of about .003 millimetres or less good spinning is obtainable. Actually the substances may be reduced to a much finer state of division, for example in the case of bariumxsulphate to a particle size of about .0003 millimetres. However there appears to be no advantage in reducing the particle size below about .001 millimetres, and in fact I prefer to employ, according to the present invention, substances having an average particle size between about .0005 and .0025 mil- 5 limetres.

just passes the filters and spinning dies.

In order to reduce as much as possible any settling of the insoluble substances in the spinning solution substances may be selected having a relatively low specific gravity and particularly a specific gravity below about 3.0 to 3.5. In this category I may mention particularly mineral silicates which are not readily decomposed by acids and which have the low specific gravity referred to above. Examples of such substances are:- the lithium and magnesium silicates or mixed silicates containing lithium and magnesium, for example members of the talc and serpentine group of minerals, petalite and lepidolite, other members of the mica. class, such as common mica or muscovite, and in addition clays, e. g. kaolin, orthoclase, microline and members of the albiteanorthite series. In the case of using these substances of relatively low specific gravity their 1 state of subdivision may be such that the spinning solution .containing the insoluble substances The invention is, however, by no means limited to these relatively light substances, and in fact from the point of View of obtaining dull. lustre I find it preferable to employ the heavier substances but reduced to a particle size of the order of g .001 to .002 millimetres. g

In order to increase the dulling effect of the insoluble substances or to decrease the quantity of insoluble substance required to produce a given degree of dulling, the insoluble substances are preferably subjected to calcination before incorporation in the spinning solution. Thus for instance the substances may be calcined at temperatures of 300-400 C. and upwards and particularly at temperatures of GOO-900 C.

The invention is more particularly applicable to the production of filaments, threads, yarns, ribbons or other products from solutions containing cellulose acetate or other cellulose esters or ethers, for example cellulose formate, cellulose propionate, cellulose butyrate, methyl cellulose, ethyl cellulose or benzyl cellulose, It may, however, also be applied to the production of filaments and other products of the cellulosic type from suitable solutions, for example viscose.

The insoluble substance or substances may be reduced to the required state of subdivision prior to incorporation in the spinning solutions by any convenient process. As stated above I prefer to attain the desired state of subdivision prior to incorporating the substance in the spinning solution or a constituent thereof. Solutions in suitable solvents of two or more reagents which will interact to form the insoluble substance or substances may be mixed under such conditions that the requisite state of subdivision results, and the use of dilute solutions is often conducive to this result. For instance, a very dilute aqueous solution of barium chloride may be mixed with a V very dilute solutionof sodium sulphate or sodium phosphate to produce a finely divided precipitate of barium Sulphate or barium phosphate. 'Alternatively the precipitation or formation may take place from'organic solutions'or from mixed aqueous organic solutions, for example 'from dilute acetic acid solutions. Qragain a finely divided substance may be formed in the solvent itself,

e. g. acetone, which issubsequently to be used formaking up the spinning solution.

Iprefer, however, to obtain the fine division of the insoluble substance by mechanical methods.

,and/or in the presence of oils, such as oleic acid, ;i linseed oil, olive 'oil or. the like.

substance may thus be brought to an aqueous or oily paste, and in this form be worked with the The insoluble solvent for making up the spinning solution or .7 with the spinning solution itself.

i junction with a cyclone-separator apparatus, to

Dispersators and/or protective colloids may likewise be present when the substance is precipitated in'the finely divided state, but in, this case a Ido not include the cellulose acetate or other Ijbase used for making up" the spinning solution 1 within the term protective colloids, since Ihave found','as previously indicated, that it is better to obtain the required state of division before incorporation of the insoluble substance with the base of the spinning solution.

Preferably the particle size of the insoluble substance to be incorporated inthe'spinning solution is as' uniform as possible, and for this reason I prefer to carry out a preliminary dry grinding whether or not a subsequent ,wet grinding is applied. ,The particles of insoluble substances which have been ground in the dry statemay be vgraded by any suitable method, and Ifind that grading by means of ,a current of air'or other gas with subsequent fractional settling from the gas current yields very good results. Forthis purpose apparatus of the'type known as the cycloneseparator may be employed; The best method I have 'yetfound is to apply adry grinding in confwet grind the graded {insoluble substance with water with or without-Turkey red oil, linseedoil or the like so as toobtain a paste containing 10 to 30% of its'weight of insoluble substance and then to work this paste with the spinning solution or with the solvent to be used therein.

If the insoluble substance itself or a reagent,

such as Turkey red oil,'used to improve-its state. of dispersion, show any acidity it is preferable to neutralize this acidity before spinning the solu- V proportion of to 4 or 5%, and particularly a proportion of about 2%, calculated on the weight tions. For thispurpose neutralizing agents, and

particularly zinc oxide, may be incorporated with the insoluble substance during it srpreparation or disintegration or may be incorporated separately in the spinning solution. a V V I The actualamount of insoluble substanceto be incorporated in the spinning solution will depend to some extent upon the nature of the substance and upon the degree of lustre required in the product. In general, however, I have found that a r 600 to 900 0.

of the cellulose acetate or other base contained in the spinning solution is suflicient to satisfythe commercial requirements of to-day' with respect.

to subdued lustre. The invention however does not exclude the addition of higher proportions,

such as 10% or more.

The spinning solutions :prepared as' described.

may be spun by methods known in the art. "The 'dry spinning of acetone or other solutions of cellulose acetate or of other cellulose esters or others is carried out in normal manner and requires no further discussion. 7 In the case of wet spinning the substance or substances incorporated in the spinning solution should be so chosen that they are substantially insoluble in the coagu-g lating bath. 7

- Novel effects may weaving, knitting or otherwise associating the filaments of modified lustre with the normal lustrous filaments of cellulose acetate or of other artificial'silks or fibres'or by associating the new filaments with otherfibres, such as cotton, wool and the like. In additionnovel yarnsor threads containing both the filaments or the likefof subdued or modified lustre and filamentsor the be produced by twisting, V

like of normal lustrema'y be producedbytwisting' another spinning nozzle, thertwisting being. ef-' fected continuously withiproduction; Or again part of the jet orifices of a single nozzle may be fed with a spinning solution containingan in soluble substance. and the remaining part of the jet orifices fed with normal spinning solution. The dull and bright filaments extruded from the single spinning jet may then beassociated and/or a twisted as desired. Fabrics prepared from such mixedf y arns or threads exhibit importantnovel effects.

If desired the 'reduced; modified" lustre effects of the presentinvention may be conjunction with the processes described in. U. S. applications S. Nos. 413,500 filed. 12th,December '1929, 423,561 filed. th January 1930 and 431,967

7 'together dull filamentsfrom one spinning nozzle with bright or normal lustrous filaments from enhanced by applying the present processes in filed 27th February.;1 930 or other. processes .de-[

signed tomodify the lustre of the artificial materials. H I What I claim and desire to secure by Letters Patent is:-1: 1

which has an average particle size of less than 0.003 millimetres.

. 1. Artificial filaments, threads, yarns, ribbons and like. materials having a reducedluster ,dueto the presence thereinofaifinely dividedpigment consisting entirely fbarium sulphate which has been heated to a temperature of 6007to 900 C. and

.2. Artificial filaments, threads, yarns, ribbons V and like materials of'organic derivatives of cellu-,

lose having a reduced luster due to. the. presence therein of 1a finely divided pigment consisting entirely of bariumsulphate which has been heated to a temperature. of 600 to .900 C(and which has an average particlesize'of lessthan 0.003 millimetres.

. 3. A spinning solution'foruse in the manufacture offilaments, threads, yarns, ribbon and like artificial materials;lwhich comprisesan. or-

ganicderivative of cellulose dissolved inan organic solvent medium, and which .contains'fine particles of a pigment consisting entirelyof barium sulphate which has been'heated to a temperature T HENRY "naEYFU s. V 

